Crediting Ghosts: W.B. Yeats and George Yeats collaborate with the dead

How on earth, we wonder, could a man of Yeatss gifts take such nonsense seriously? exclaimed W.H. Auden. How could Yeats take up something so essentially lower-middle class or should I say Southern Californian? Audens incredulous geography was more right than he knew. Perhaps the peak of Yeatss life-long interest in what Auden dismissively called the mumbo jumbo of magic (mediums, spells, the Mysterious Orient - how embarrassing) were the sleeps, joint experiments by W.B. Yeats and his young wife George, began in earnest in a railway carriage somewhere near Pasadena in Southern California. During an American lecture tour, in one of those little sleeping compartments in a train, as Yeats remembered, my wife, who had been asleep for some minutes, began to talk in her sleep, and from that on almost all communications came in that way. So emerged into hearing the most extraordinary of modernist collaborations. Answering Audens half-mocking challenges (or probing the explanations of Freud or the Yeatses themselves) turns on questions of credit. How is a properly sceptical scholar to credit such phenomena - and how are they to ascribe credit to those involved?